Vapor generating plant

ABSTRACT

A plurality of vapor generators are connected in common to a single water separator. Collars are used to connect the generators to the separators and the collars can be welded together in the field. The water which is separated out in the separator is returned to the vapor generators and mixed in with the cold feed water.

n4 15 16 las 35 Ill l Hi f t U United States Patent 1 3,682,140 Roffler[451 Aug. 8, 1972 v VAPOR GENERATING PLANT 2,220,045 10/1950 Kraft et a]..l22/32 72 Inventor; Josua Rome Wimenhur, Switzep 3,267,907 8/ 1966Glausser et al. ..l22/34 land 3,209,731 10/ 1965 Schonberger et al..l22/483 Assigneez Sui?" Brothers, Ltd, winterthur, 2,373,564 4/1945Huff ..l22/34 swltzerland Primary Examiner-Kenneth W. Sprague [22]Filed: April 13, 1970 Attorney-Kenyon & Kenyon Reilly Carr & Chapin [21]Appl. No.: 27,810

. 57 ABSTRACT Fowign Application Priority Data A plurality of vaporgenerators are connected in com- A l mon to a single water separator.Collars are used to pr: 5, 1969 Switzerland ..5646/69 connect thegenerators to the separatom and the 52 us. Cl ..122/34, 122/483 can bewelded math" in The [51] Int. Cl ..F22b l/02 which is Separated out inthe separator is returned to 58 Field of Search ..122/32, 34, 483 thevapor generators and mixed in with the cold feed water. 56 R r 1 e 9""CM 8 Claims, 1 Drawing figure UNITED STATES PATENTS 2,796,050 6/1957Rehm 122/32 PATENTEDAUS a 1912 In ventor: dosun QOF'FLEQ ATTORNESG VAPORGENERATING PLANT- This invention relates to a vapor generating plant andmore particularly to a vapor generating plant having a plurality ofvapor generating sections.

Vapor generating plants have been known which have a vapor generator anda water separator situated above the generator. However, where thegenerator has been constructed for high outputs, the tube plate of thegenerator has been very thick (up to 500 mm) and very large, andtherefore very heavy and expensive. Further, in the manufacture of suchlarge tube plates, various operations, for example, the drilling of thevery large number of required holes (up to l7,000) takes a very longtime.

In order to overcome these disadvantages, the large generators have beenreplaced by a number of small vapor generators arranged in parallel. Thedisadvantage of this solution, however, is that it is difficult toprovide the space required to house all the water separators connectedto the vapor generators. Also, such requires separate heat insulationfor the separate vapor generators. Further, the production of aplurality of water separators is troublesome and expensive.

Accordingly, it is an object of the invention to provide a vaporgenerating plant with a water separating section of relatively smallsize to service a plurality of vapor generators.

It is another object of the invention to provide a vapor generatingplant which can be produced for relative low cost in an economicalmanner.

It is another object of the invention to provide a structural unit whichis light and compact.

It is another object of the invention to enclose the entirevapor-generating section of a vapor generating plant in common thermalinsulation.

Briefly, the invention provides a vapor generating plant with aplurality of vapor generators which are connected to a common waterseparator.

The vapor generators are each constructed so as to generate vapor from asupply of fluid such as water and are all connected in common to thewater separator so as to deliver all the generated vapor into theseparator. The separator is made, for example, as a spherical vessel andconnects to a plurality of the generators, for example, four, by meansof collars which can be welded together in a simple operation. Inaddition, the separator houses liquid or water separating units toseparate out water from the vapor as well as a spigot which leads thevapor to a steam circuit. The separator can also have a superheatingelement mounted therein to supply heat to the vapor before the vaporpasses out of the spigot.

The water separator is further connected to the vapor generators so asto direct the separated water back into each generator via the jacketsconnecting the separator to the generators.

The generators and separator are further surrounded by common thermalinsulation and can be connected into various systems such as into thecoolant circuits of a nuclear reactor to establish a heat exchange pathfor the heated coolant passing out of a nuclear reactor.

These and other objects and advantages of the invention will become moreapparent from the following detailed description and appended claimstaken in conjunction with the accompanying drawing in which:

The FIGURE illustrates a vapor generating plant according to theinvention partly in cross-section.

Referring to the FIGURE, the vapor generating plant has a vaporgenerating section 1, a water separating section 2 and a flow circuit 3such as a steam circuit for a secondary medium. The vapor generatingsection comprises four similar vapor generators 4, 5, 6, 7 two of whichare shown and two of which are only shown diagrammatically. The waterseparating section comprises a spherical vessel 8, which is common toall four vapor generators and into which these generators lead.

Each vapor generator 4, 5, 6, 7 has a pressure vessel 10 containingaxially arranged heating surfaces, for example, a nest of U-tubes 11,whose ends are fixed in a tube plate 12. A spherical base 13 is weldedto the vessel 10 beneath the tube plate 12 and has a partition 14located in the space between thebase 13 and plate 12 to define an inletchamber 15 and outlet chamber 16 for the primary medium of the vaporgenerator. The primary medium enters through .an inlet spigot 17 on thespherical base 13 passes upwardly in the tubes 11 and then downwardlyinto the outlet chamber 16 and leaves through an outlet spigot 18.

In addition, a lining tube 21 is mounted in each vessel 10 by suitablemeans (not shown), e.g., by brackets on the pressure vessel wall 20,between the nest of tubes 11 and the wall 20 of the pressure vessel.This lining tube 21 extends upwardly into the spherical separator vessel8 by means of an extension which comprises a conical portion 22 and acylindrical portion 24 in which a twist-type water separator 23 ismounted. The cylindrical portion 24 of the lining tube extension issurrounded in spaced relation by a jacket 25 to define an annular gap 26therebetween. The jacket 25 is formed by a collar 25a attached to thespherical vessel 8 and a collar 25b attached to an upper sphericalportion 27 of the pressure vessel 18 and the two collars 25a, 25b arewelded together at 25c. The lining tube 21 extends downwards to acertain distance above the tube plate 12 in order to leave a gap 28. Anannular chamber 29 which is formed between the spherical portion 27 ofthe pressure vessel 10 and the conical portion 22 of the tube lining 21contains a perforated feedwater distributing ring 30 connected to afeed-water line 31 of the secondary medium circuit 3.

All four vapor generators are connected in parallel to the feed-waterline 31. The cold feed water falls out of the annular chamber 29 into anannular gap 32 between the lining tube 21 and pressure-vessel wall 20,passing at the bottom through the gap 28 into the zone occupied by thenest of tubes 11. Each vapor generator is connected in parallel to acoolant circuit 35 for a nuclear reactor 36. The coolant, herepressurized water, is supplied by a pump 37. The circuit contains apressure-maintaining means 38 for the coolant. As shown, one generator 4is connected to the coolant circuit by branch lines and 46, anothergenerator 5 by branch lines 47 and 48 and the remaining generators 6 and7 communicate with the coolant circuit in a similar manner by way ofbranch lines, 49, 50 and 51, 52 respectively.

The spherical vessel 8, which is in two halves 8a and 8b contains waterseparating elements 55 and a superheater 56. The dry steam, which is thesecondary medium, leaves through a live-steam spigot 57 in the top ofthe vessel 8 and enters the circuit 3 for the secondary medium. Thiscircuit 3 contains a turbine 58 with an electric generator 59, acondenser 50, a condensate pump 61, two preheaters 62, a feed-watervessel 63, a feed-water pump 64 and a feed-water valve 65. A pressureconverter 66 generates a signal corresponding to the water level 67 inthe spherical vessel 8 and used by a controller 63 to control thefeed-water valve 65 in the feed-water line 31.

The operation of the plant will be described with reference to generator4 for purposes of simplicity.

The coolant for the nuclear reactor 36, that is, the primary or heatingmedium for the vapor generators, flows out of the circuit 35 by way ofthe branch line 45 and the inlet spigot 17 of the vapor generator 4 intothe inlet chamber of this generator. Next, the medium spreads throughthe approximately 2,000 parallel tubes in the nest 11 in heat exchangerelation with the upward flow of secondary medium (water) surroundingthe tubes. The primary medium leaving the nest of tubes collects in theoutlet chamber 16 and flows by way of the outlet spigot 18 and branchline 46 back into the nuclear reactor circuit 35. The secondary mediumsurrounding the tubes in the nest is heated and partially evaporated.The bubbles of steam reduce the specific gravity of the water, causing astrong upward flow in the water. The water/steam mixture passes throughthe upper portions 22, 24 of the lining and is caused to rotate in thetwist-type water separator 23, so that coarse separation of the waterand steam occur due to centrifugal action. The separated water collectsin the bottom of the spherical vessel 8. The steam, which still containsa large proportion of water, flows on to the water separator elements55, where all but a negligible proportion of the water is separated.This water, also, collects in the bottom of the spherical vessel 8,where a water reserve forms, whose level is indicated at 67 and whichcommunicates through the annular gap 26 with the water in the annulargap 32 in the pressure vessel and mixes therein with the cold feedwater. Since water is yielded in only one water separator, its level caneasily be regulated by means of the single controller 68. The steamflows through the superheater 56 to the livesteam spigot 57 and theninto the circuit 3. The steam expanded in the turbine 58 is condensed inthe condenser 60. The condenser pump 61 then feeds the secondary mediumthrough the preheaters 62 into the feed-water vessel 63 and then thesecondary medium is fed by the pump 64 to the feed-water line 31 for thevapor generators.

The vapor generating section of the plant therefore comprises foursimilar vapor generators 4 to 7, which can be completed separately in afactory. The lower hemisphere 8a of the spherical vessel is providedwith four collars 25a. In order to build the plant, the four is easilyand rapidly assembled. Little welding is carried out on site, and onlyannular welds are required. The four vapor generators are then enclosedover their entire length in common thermal insulation (only part ofwhich is shown). The spherical vessel may also be enclosed in thisinsulation.

at is claimed is: vapor generating plant comprising a vapor generatingsection having a plurality of pressure vessels for generating vaporvtherein, each pressure vessel having a plurality of tubes therein forpassing a primary medium therethrough in heat exchange relation with asecondary medium passing into said pressure vessel to generate the vaporfrom the secondary medium;

a water separating section having a separating vessel therein connectedin common to said pressure vessels to receive the generated vaportherefrom; and

a lining surrounding said tubes in each pressure vessel, said lininghaving an extension thereof extending into said separating vessel todirect the generated vapor into said separating vessel.

2. A vapor generating plant as set forth in claim 1 wherein saidseparating vessel is connected to said pressure vessels to returnseparated water from the generated vapor passing therethrough to saidpressure vessels.

3. A vapor generating plant as set forth in claim 2 which furthercomprises means connected to each pressure vessel to direct a flow offresh feed water into each pressure vessel, and means for measuring thelevel of separated water in said separating vessel to control the flowof fresh feed water into each pressure vessel in dependence upon thelevel of separated water in said separating vessel.

4. A vapor generating plant as set forth in claim 1 wherein saidseparating vessel is spherical and wherein said water separating sectionfurther includes a water separating element and a superheating elementtherein in the path of flow of the vapor passing therethrough.

5. A vapor generating plant as set forth in claim 1 which furtherincludes a jacket disposed in spaced relation to said lining extensionto define an annular gap therebetween for directing collected liquid insaid separating vessel back into each pressure vessel.

6. A vapor generating plant as set forth in claim 1 which furtherincludes means in said lining extension for producing a twist in theflow of vapor passing into said separating vessel.

7. A vapor generating plant as set forth in claim 1 wherein each saidpressure vessel has a wall spaced from said lining to define an annularspace for the flow of secondary medium into said pressure vessel and aninlet for fresh secondary medium communicating with said annular space.

8. A vapor generating plant as set forth in claim 1 which furthercomprises thermal insulation surrounding said pressure vessels incommon.

1. A vapor generating plant comprising a vapor generating section havinga plurality of pressure vessels for generating vapor therein, eachpressure vessel having a plurality of tubes therein for passing aprimary medium therethrough in heat exchange relation with a secondarymedium passing into said pressure vessel to generate the vapor from thesecondary medium; a water separating section having a separating vesseltherein connected in common to said pressure vessels to receive thegenerated vapor therefrom; and a lining surrounding said tubes in eachpressure vessel, said lining having an extension thereof extending intosaid separating vessel to direct the generated vapor into saidseparating veSsel.
 2. A vapor generating plant as set forth in claim 1wherein said separating vessel is connected to said pressure vessels toreturn separated water from the generated vapor passing therethrough tosaid pressure vessels.
 3. A vapor generating plant as set forth in claim2 which further comprises means connected to each pressure vessel todirect a flow of fresh feed water into each pressure vessel, and meansfor measuring the level of separated water in said separating vessel tocontrol the flow of fresh feed water into each pressure vessel independence upon the level of separated water in said separating vessel.4. A vapor generating plant as set forth in claim 1 wherein saidseparating vessel is spherical and wherein said water separating sectionfurther includes a water separating element and a superheating elementtherein in the path of flow of the vapor passing therethrough.
 5. Avapor generating plant as set forth in claim 1 which further includes ajacket disposed in spaced relation to said lining extension to define anannular gap therebetween for directing collected liquid in saidseparating vessel back into each pressure vessel.
 6. A vapor generatingplant as set forth in claim 1 which further includes means in saidlining extension for producing a twist in the flow of vapor passing intosaid separating vessel.
 7. A vapor generating plant as set forth inclaim 1 wherein each said pressure vessel has a wall spaced from saidlining to define an annular space for the flow of secondary medium intosaid pressure vessel and an inlet for fresh secondary mediumcommunicating with said annular space.
 8. A vapor generating plant asset forth in claim 1 which further comprises thermal insulationsurrounding said pressure vessels in common.